  function getDisplayTempValue(value){
    var unit = localStorage.getItem("unit");

    if(unit == "centigrade")
        return value;
    else if(unit == "fahrenheit")
        return tempC2F(value);
  }

  // 摄氏度 转化为 华摄氏度
  function tempC2F(temp){
    if(temp == "-")
        return "-";

	return (1.8 * temp + 32).toFixed(2);
  }

  function getTempUnit(){
    var unit = localStorage.getItem("unit");

    if(unit == "centigrade")
        return " ℃";
    else if(unit == "fahrenheit")
        return " ℉";
  }